My chain runs perfectly smoothly through the chain tensioner and around the sprocket when on the work stand but as soon as I put any resistance through it the chain rides up on the sprocket and slips.

Its as if the distance between the chain links is increasing meaning each link is too long to fit between the sprocket teeth.

I’ve adjusted the chain line from perfect to miles out and it doesn’t seem to make any difference.

The chain is a brand new sram 9 speed, maybe not the best SS chain but being brand new I can’t see it being an issue.

The alfine sprocket is second hand but looks like it has quite a lot of life left in it.

Any suggestions?

Thanks

Is the sprocket designed for a 1-8th chain? As a SS chain and a 9speed are different thicknesses. This would cause the problem.

Er… Never thought about that. Also I have no idea if the Alfine sprocket is designed for one or the other.

Honest question. why would the width make any difference when it seems to be the length causing the problem?

as above, id say that the 9spd chain which is designed to ride up as soon as it receives side load from a sprocket tooth, with a 1/8th tooth probably is the cause.

I recently swapped my 9spd chain off the SS for a SS specific chain as I was getting problems when honking the pedals – the rear triangle was deforming sufficiently for the chain side plates to engage with the sprocket and derail even when the surly tugnut was tight as a banjo string.

its not the length. All normal sprockets and chainrings are designed around a 1/2″ pitch. It looks like length because the chain link is riding up the tooth out of the valley.

If the sprocket is too wide for the chain to fit in the chain it will ride up the sprocket trying to throw it off. You should have a little play (side to side) if the chain is the correct fit. If it’s a 9speed chain in a SS/1-8th sprocket it will have no play

SS chain for the win!

having run no end of bodged ss and fixies with whatever old bits I had in the spares box I was a bit surprised the new chain didn’t work but I’ll give a proper ss chain a go.

any recommendations?

Izumi chain! Used on track bikes cheap and strong!!

ace, thanks for all that

I’m back.

Just fitted a sram PC-1 1/8th chain and its made no difference at all.

Any more suggestions?

worn sprocket

^ if it really is slipping up over the teeth thats the only thing left to explain it.

How old/knackered is it?

Just had exactly the same problem,fit new chain jumping and slipping adjusted cable tension to no avail.
Had another look this evening discovered wheel not sat in dropouts correctly.
Put bike on floor released quick release, retightend and gears now perfect.
Feel like a right wally but pleased its cured

I’m thinking it could be the sprocket as well, cant be anything else really can it? Hopefully JRA can sort me out.

Dadandlad, I’ve done similar silly things in the past but this time i know its all sat properly.

if its not the sprocket the only other thing i think it could be is that your chain alignment is slightly out and your sproket is a bit fusy and throwing it off.

if it always throws outwards then try spacing it outwards, if it always throws inwards then try spacing it inwards. probably only need to adjust it a few mm at a time.
worth a bit of trial and error before you splash on a sproket.

though it does sound like the sproket is the issue.

Dadandlad, I’ve done similar silly things in the past but this time i know its all sat properly.

Spent two rides trying to sort it out 😳

dobo, from my first post

I’ve adjusted the chain line from perfect to miles out and it doesn’t seem to make any difference.

If the sprocket’s worn, is it reversible like Rohloff ones?

I’ve mailed a couple of local places to see if they can sort me out with a new one and fit it as its a bit of a bugger

new sprocket seems to have done the trick so far